Our showering under running hot water is similarly stupid waste of energy. Water could easily be recycled within the shower session, much like in a dishwasher,

Our showering under running hot water is similarly stupid waste of energy. Water could easily be recycled within the shower session, much like in a dishwasher, if we cared about saving energy there. (Or heat could be recovered from the exiting water) A running hot water tap is probably the most enery intensive thing you can turn on in your home. 20+ kilowatts. If it's heated with electricity, 50+ kilowatts of fossil fuels are probably being burned to run it.